1. Field of the Invention
The present invention generally relates to a probe used for an optical memory such as an optical disc, an optical card, an optical tape, or the like, to which information is recorded, from which information is reproduced, and from which information is erased, using light, and, in particular, to a near field optical probe which generates the optical near field and detects scattered light generated through the optical near field and a manufacturing method thereof.
2. Description of the Related Art
In an optical memory, which has been put to practical use, a laser spot, obtained from converging laser light to the diffraction limit, is caused to be incident on a recording medium. At this time, information is recorded on the recording medium as a result of thermal and magnetic modulation being performed on a recording layer of the recording medium. Further, by detecting the intensities of reflected light modulated by record bits, the information is reproduced. In such information recording means, the recording density of the recording medium is approximately determined by the laser wavelength. In order to cope with a recent increase in an information amount processed in various types of information apparatuses such as computers and so forth, a large-capacity memory which achieves a recording density which is obtained as a result of the diffraction limit being exceeded has been demanded. As a promised next-generation large-capacity memory such as that mentioned above, an optical memory on which information recording, reproducing and erasing are performed using the optical near field was proposed. Examples thereof will now be described.
(1) ‘Near Field Optics and Its Application to Optical Memory,’ a thesis journal of the Institute of Electronics, Information and Communication Engineers, C-I, Vol. J81-C-I, No. 3, Pages 119–126, March, 1998, proposes a device in which a two-dimensional aperture row is formed in a silicon substrate using a semiconductor-plane-process technique, and the optical near fields are generated on the apertures by light which has been incident on the top surface of the silicon substrate. Further, this literature suggests a possibility of integration with a photodetector array.
(2) Japanese Laid-Open Patent Application No. 9-198830 discloses that, in a high-density recording apparatus using the optical near field, in order to stably generate the optical near field in proximity to a recording medium, a high-density recording is performed using a slider in which a circular-cone-shape through hole having an aperture is provided.
Thus, the device in which the two-dimensional aperture row is formed in the silicon substrate using the semiconductor-plane-process technique, and the optical near fields are generated on the apertures by light which has been incident on the top surface of the silicon substrate, was proposed. When a photodetector is integrated into such a device, it is possible to miniaturize such a near field optical probe, and to improve efficiency in detection because it is possible that scattered light and so forth generated through the optical near field can be received in the proximity.